基于gdiplus的游动效果，学习gdiplus的参考-Based on gdiplus the swimming effect, a reference to learn gdiplus

双缓冲绘制的金鱼游动和碰撞程序，金鱼动态方向变更，无任何闪屏-Double-buffered rendering and collision procedures goldfish swimming goldfish dynamic direction change, without any splash screen